we had a bad abex pump on #1 eng. swapped out with parker and ran engines. all ops cks were good. original write up was landing gear down and pump light came on. so we recreated it and nothing. we ended doing it again with #2 pump off and went flaps down and while moving flight controls (not what i was supposed to do but new to hydraulics and did it thinking everything would ck good) and pressure dropped to 700 and the pump light came on. switched #1 off and put #2 on (parker pump) and the pressure dropped to 2000 with no light. switched pumps from #1 to #2 and #2 to #1, issue followed pump. been told this is normal but just doesnt make much sense to me, because of the issue of losing the engine with abex on it.
scenarios:
one engine flaps and flight controls moving
parker 700 psi
abex 2000 psi
one engine just flaps
parker 1200 psi
abex 2500 psi
one engine just flight controls
parker 3000 psi +/- 200 psi
abex 3000 psi +/- 200 psi
both engines all tests
3000 psi